David Miliband quick off the mark to announce his leadership bid

Wednesday 12 May 2010 07:48 BST

Not standing: Alan Johnson has ruled himself out of a leadership battle

David Miliband was first out of the traps in the race for the Labour leadership today.

The former foreign secretary announced his candidacy for the position outside the Commons immediately after the first post-election meeting of Labour MPs. Although long-expected, Mr Miliband's decision to act swiftly and seize his chance was aimed at trying to build an unstoppable momentum in the contest to succeed Gordon Brown, who resigned yesterday.

Mr Miliband's critics have accused him of dithering over previous opportunities to take the leadership and allies felt there was no point in holding back until next week.

His campaign received a huge early boost when Alan Johnson, himself seen as a possible caretaker leader, announced he would not run for the top job and instead gave his full backing to Mr Miliband.

Mr Johnson reflected the urgency in the Miliband team when he became the first Cabinet minister to publicly back his colleague and said it was time to transfer power to the next generation.

He said that "baby boomers" like himself and acting leader Harriet Harman should make way for their younger colleagues.

"We have such an exceptional pool of talent and I think David's the best," Mr Johnson said, adding that he will turn 60 on Monday — and that while he "deplored ageism", the younger generation should take over.

Mr Johnson said that he wanted "as many hats in the ring as possible". Ed Balls, Ed Miliband, Andy Burnham and Jon Cruddas are all expected to stand but held back today from going public too soon.

The former home secretary said that Labour needed to "regroup" and "refresh" during five years in opposition and predicted the leader's job was likely to span at least 13 years.

He warned that the party could not repeat Mr Brown's "coronation" in 2007, when no other candidate was able to muster the backing of fellow MPs needed to challenge for the job. Would-be candidates currently need 33 MPs to back their bid.

He told the BBC: "I think David is the greatest talent. I think he is a remarkable politician and his talent is to put very complex ideas into clear language, so I will be backing him.

"We need the broadest possible contest, having had the narrowest possible contest when Gordon took over. So as many hats in the ring as possible, but one of them won't be mine."

Labour's ruling National Executive Committee will meet to determine the timetable and procedures for electing a new leader.

Mr Miliband's younger brother Ed will make a test-the-waters speech to Labour activists on Saturday. An "EM4Leader" campaign has started on Twitter.